This video shows flying a plane at the air-port. Caveat: Their method is only available close to the end of the game because it requires a vehicle that you may not get, depending on your decision in the story. The barn storm lasts from 2:03 to 2:07, earning $10,216. This video claims $40-80K per minute at the air-port. Restart will take a little over 4 minutes and 20 seconds = 260 seconds. My record, with a partner, for cash is $24,907, in medium SERC. Let's be generous and round: 12K/3 = 4K/minute.

This video claims $10,000+ (e.g., $11,913) in three minutes with Professor Genki's Super Ethical Reality Climax. These methods are aside from buying as many properties as possible to earn money over time passively, aside from buying that money DLC, aside from completing the missions that have bigger cash rewards, and certain other things. Source means stuff like which activity or diversion, the difficulty level if it's an activity, or the vehicle and location if it's a barn-storm. I was initially emphasizing the fonts of key aspects of each method, but there are too many, so instead I'll simply tell you what to look out for: source and cash per unit time.

Saints row 3 money glitch